Why Rats?

The forcible insertion of GM genes to add a new trait to
a crop unavoidably affects expression of other unrelated genes, which may or
may not affect nutritional quality and toxicity. Such changes cannot be
predicted prior to consumption because researchers do not know what they are
looking for. Animal feeding trials are one of the few ways to identify possible
risks from unintended changes in the GMO.

Rats are often used in GMO feeding trials because like
humans, they are mammals and have a similar digestive system and metabolism.

Why
this strain of rat?

The strain of rat used in Séralini’s experiment was the
Sprague-Dawley, a common choice for long-term toxicity and carcinogenicity studies
performed by industry and independent scientists alike.[1-6]

This was also the same strain of rat used by Monsanto in
its short 90-day study[7]
on the same GM maize that Séralini studied over the long term. Séralini used
the same strain of rat in order that his experiment would be comparable with
Monsanto’s.

While critics of Séralini’s study
claim that the Sprague-Dawley is an unusually tumour-prone strain of rat, in
fact it is about as prone to developing tumours as humans living in
industrialized countries. For this reason, researchers view it as an excellent
human-equivalent model for long-term toxicity and carcinogenicity tests.[8]